diff --git a/mayan/apps/acls/models.py b/mayan/apps/acls/models.py
index 171938c8be..800773dc75 100644
--- a/mayan/apps/acls/models.py
+++ b/mayan/apps/acls/models.py
@@ -70,6 +70,9 @@ class AccessControlList(models.Model):
         )
 
     def get_permission_titles(self):
+        """
+        Returns the descriptibe labels for the permissions.
+        """
         result = ', '.join(
             [force_text(permission) for permission in self.permissions.all()]
         )
diff --git a/mayan/apps/cabinets/models.py b/mayan/apps/cabinets/models.py
index 014d304285..d6fbe493f3 100644
--- a/mayan/apps/cabinets/models.py
+++ b/mayan/apps/cabinets/models.py
@@ -19,6 +19,12 @@ from .search import cabinet_search  # NOQA
 
 @python_2_unicode_compatible
 class Cabinet(MPTTModel):
+    """
+    Model to store a hierarchical tree of document containers. Each container
+    can store an unlimited number of documents using an M2M field. Only
+    the top level container is can have an ACL. All child container's
+    access is delegated to their corresponding root container.
+    """
     parent = TreeForeignKey(
         blank=True, db_index=True, null=True, on_delete=models.CASCADE,
         related_name='children', to='self'
@@ -41,6 +47,10 @@ class Cabinet(MPTTModel):
         return self.get_full_path()
 
     def add_document(self, document, user=None):
+        """
+        Add a document to a container. This can be done without using this
+        method but this method provides the event commit already coded.
+        """
         self.documents.add(document)
         event_cabinets_add_document.commit(
             action_object=self, actor=user, target=document
@@ -50,14 +60,26 @@ class Cabinet(MPTTModel):
         return reverse('cabinets:cabinet_view', args=(self.pk,))
 
     def get_document_count(self, user):
+        """
+        Return numeric count of the total documents in a cabinet. The count
+        is filtered by access.
+        """
         return self.get_documents_queryset(user=user).count()
 
     def get_documents_queryset(self, user):
+        """
+        Provide a queryset of the documents in a cabinet. The queryset is
+        filtered by access.
+        """
         return AccessControlList.objects.filter_by_access(
             permission_document_view, user, queryset=self.documents
         )
 
     def get_full_path(self):
+        """
+        Returns a string that represents the path to the cabinet. The
+        path string starts from the root cabinet.
+        """
         result = []
         for node in self.get_ancestors(include_self=True):
             result.append(node.label)
@@ -65,17 +87,22 @@ class Cabinet(MPTTModel):
         return ' / '.join(result)
 
     def remove_document(self, document, user=None):
+        """
+        Remove a document from a cabinet. This method provides the
+        corresponding event commit.
+        """
         self.documents.remove(document)
         event_cabinets_remove_document.commit(
             action_object=self, actor=user, target=document
         )
 
     def validate_unique(self, exclude=None):
-        # Explicit validation of uniqueness of parent+label as the provided
-        # unique_together check in Meta is not working for all 100% cases
-        # when there is a FK in the unique_together tuple
-        # https://code.djangoproject.com/ticket/1751
-
+        """
+        Explicit validation of uniqueness of parent+label as the provided
+        unique_together check in Meta is not working for all 100% cases
+        when there is a FK in the unique_together tuple
+        https://code.djangoproject.com/ticket/1751
+        """
         with transaction.atomic():
             if connection.vendor == 'oracle':
                 queryset = Cabinet.objects.filter(parent=self.parent, label=self.label)
@@ -102,6 +129,11 @@ class Cabinet(MPTTModel):
 
 
 class DocumentCabinet(Cabinet):
+    """
+    Represent a document's cabinet. This Model is a proxy model from Cabinet
+    and is used as an alias to map columns to it without having to map them
+    to the base Cabinet model.
+    """
     class Meta:
         proxy = True
         verbose_name = _('Document cabinet')
diff --git a/mayan/apps/checkouts/models.py b/mayan/apps/checkouts/models.py
index 43a38d8848..490d658152 100644
--- a/mayan/apps/checkouts/models.py
+++ b/mayan/apps/checkouts/models.py
@@ -22,7 +22,7 @@ logger = logging.getLogger(__name__)
 @python_2_unicode_compatible
 class DocumentCheckout(models.Model):
     """
-    Model to store the state and information of a document checkout
+    Model to store the state and information of a document checkout.
     """
     document = models.OneToOneField(
         on_delete=models.CASCADE, to=Document, verbose_name=_('Document')
@@ -99,6 +99,9 @@ class DocumentCheckout(models.Model):
 
 
 class NewVersionBlock(models.Model):
+    """
+    Model to keep track of which documents have new version upload restricted.
+    """
     document = models.ForeignKey(
         on_delete=models.CASCADE, to=Document, verbose_name=_('Document')
     )
diff --git a/mayan/apps/common/models.py b/mayan/apps/common/models.py
index 1f4209c79a..41f736c700 100644
--- a/mayan/apps/common/models.py
+++ b/mayan/apps/common/models.py
@@ -20,6 +20,10 @@ def upload_to(instance, filename):
 
 
 class ErrorLogEntry(models.Model):
+    """
+    Class to store an error log for any object. Uses generic foreign keys to
+    reference the parent object.
+    """
     namespace = models.CharField(
         max_length=128, verbose_name=_('Namespace')
     )
@@ -46,6 +50,10 @@ class ErrorLogEntry(models.Model):
 
 @python_2_unicode_compatible
 class SharedUploadedFile(models.Model):
+    """
+    Keep a database link to a stored file. Used to share files between code
+    that runs out of process.
+    """
     file = models.FileField(
         storage=storage_sharedupload, upload_to=upload_to,
         verbose_name=_('File')
@@ -76,6 +84,10 @@ class SharedUploadedFile(models.Model):
 
 @python_2_unicode_compatible
 class UserLocaleProfile(models.Model):
+    """
+    Stores the locale preferences of an user. Stores timezone and language
+    at the moment.
+    """
     user = models.OneToOneField(
         on_delete=models.CASCADE, related_name='locale_profile',
         to=settings.AUTH_USER_MODEL, verbose_name=_('User')
diff --git a/mayan/apps/django_gpg/models.py b/mayan/apps/django_gpg/models.py
index 5569ee692a..1731532efb 100644
--- a/mayan/apps/django_gpg/models.py
+++ b/mayan/apps/django_gpg/models.py
@@ -65,6 +65,9 @@ class Key(models.Model):
         return '{} - {}'.format(self.key_id, self.user_id)
 
     def clean(self):
+        """
+        Validate the key before saving.
+        """
         import_results = gpg_backend.import_key(key_data=self.key_data)
 
         if not import_results.count:
@@ -78,6 +81,9 @@ class Key(models.Model):
 
     @property
     def key_id(self):
+        """
+        Short form key ID (using the first 8 characters).
+        """
         return self.fingerprint[-8:]
 
     def save(self, *args, **kwargs):
@@ -101,13 +107,15 @@ class Key(models.Model):
         super(Key, self).save(*args, **kwargs)
 
     def sign_file(self, file_object, passphrase=None, clearsign=False, detached=False, binary=False, output=None):
-        # WARNING: using clearsign=True and subsequent decryption corrupts the
-        # file. Appears to be a problem in python-gnupg or gpg itself.
-        # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=55647
-        # "The problems differ from run to run and file to
-        # file, and appear to be due to random data being inserted in the
-        # output data stream."
-
+        """
+        Digitally sign a file
+        WARNING: using clearsign=True and subsequent decryption corrupts the
+        file. Appears to be a problem in python-gnupg or gpg itself.
+        https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=55647
+        "The problems differ from run to run and file to
+        file, and appear to be due to random data being inserted in the
+        output data stream."
+        """
         file_sign_results = gpg_backend.sign_file(
             file_object=file_object, key_data=self.key_data,
             passphrase=passphrase, clearsign=clearsign, detached=detached,
diff --git a/mayan/apps/document_comments/models.py b/mayan/apps/document_comments/models.py
index 016591aae2..743e2de588 100644
--- a/mayan/apps/document_comments/models.py
+++ b/mayan/apps/document_comments/models.py
@@ -18,6 +18,9 @@ logger = logging.getLogger(__name__)
 
 @python_2_unicode_compatible
 class Comment(models.Model):
+    """
+    Model to store one comment per document per user per date & time.
+    """
     document = models.ForeignKey(
         db_index=True, on_delete=models.CASCADE, related_name='comments',
         to=Document, verbose_name=_('Document')
diff --git a/mayan/apps/document_indexing/models.py b/mayan/apps/document_indexing/models.py
index 528d92e1ca..90b3afa2a5 100644
--- a/mayan/apps/document_indexing/models.py
+++ b/mayan/apps/document_indexing/models.py
@@ -77,6 +77,14 @@ class Index(models.Model):
         )
 
     def index_document(self, document):
+        """
+        Method to start the indexing process for a document. The entire process
+        happens inside one transaction. The document is first removed from all
+        the index nodes to which it already belongs. The different index
+        templates that match this document's type are evaluated and for each
+        result a node is fetched or created and the document is added to that
+        node.
+        """
         logger.debug('Index; Indexing document: %s', document)
 
         with transaction.atomic():
@@ -131,10 +139,18 @@ class Index(models.Model):
 
     @property
     def template_root(self):
+        """
+        Return the root node for this index.
+        """
         return self.node_templates.get(parent=None)
 
 
 class IndexInstance(Index):
+    """
+    Model that represents an evaluated index. This is an index whose nodes
+    have been evaluated against a series of documents. If is a proxy model
+    at the moment.
+    """
     class Meta:
         proxy = True
         verbose_name = _('Index instance')
@@ -286,6 +302,12 @@ class IndexTemplateNode(MPTTModel):
 
 @python_2_unicode_compatible
 class IndexInstanceNode(MPTTModel):
+    """
+    This model represent one instance node from a index template node. That is
+    a node template that has been evaluated against a document and the result
+    from that evaluation is this node's stored values. Instances of this
+    model also point to the original node template.
+    """
     parent = TreeForeignKey(
         blank=True, null=True, on_delete=models.CASCADE, to='self',
     )
@@ -311,6 +333,9 @@ class IndexInstanceNode(MPTTModel):
         return self.value
 
     def delete_empty(self):
+        """
+        Method to delete all empty node instances in a recursive manner.
+        """
         # Prevent another process to delete this node.
         try:
             lock = locking_backend.acquire_lock(
@@ -374,6 +399,9 @@ class IndexInstanceNode(MPTTModel):
         return 'indexing:index_instance_node_{}'.format(self.pk)
 
     def index(self):
+        """
+        Return's the index instance of this node instance.
+        """
         return IndexInstance.objects.get(pk=self.index_template_node.index.pk)
 
     def remove_document(self, document):
@@ -399,6 +427,11 @@ class IndexInstanceNode(MPTTModel):
 
 
 class DocumentIndexInstanceNode(IndexInstanceNode):
+    """
+    Proxy model of node instance. It is used to represent the node instance
+    in which a document is currently located. It is used to aid in column
+    registration. The inherited methods of this model should not be used.
+    """
     objects = DocumentIndexInstanceNodeManager()
 
     class Meta:
diff --git a/mayan/apps/document_parsing/models.py b/mayan/apps/document_parsing/models.py
index 066bc4996d..4fad137201 100644
--- a/mayan/apps/document_parsing/models.py
+++ b/mayan/apps/document_parsing/models.py
@@ -11,6 +11,9 @@ from .managers import DocumentPageContentManager, DocumentTypeSettingsManager
 
 @python_2_unicode_compatible
 class DocumentPageContent(models.Model):
+    """
+    This model store's the parsed content of a document page.
+    """
     document_page = models.OneToOneField(
         on_delete=models.CASCADE, related_name='content', to=DocumentPage,
         verbose_name=_('Document page')
@@ -33,6 +36,9 @@ class DocumentPageContent(models.Model):
 
 
 class DocumentTypeSettings(models.Model):
+    """
+    This model stores the parsing settings for a document type.
+    """
     document_type = models.OneToOneField(
         on_delete=models.CASCADE, related_name='parsing_settings',
         to=DocumentType, unique=True, verbose_name=_('Document type')
@@ -56,6 +62,10 @@ class DocumentTypeSettings(models.Model):
 
 @python_2_unicode_compatible
 class DocumentVersionParseError(models.Model):
+    """
+    This module stores the errors captures when attempting to parse a
+    document version.
+    """
     document_version = models.ForeignKey(
         on_delete=models.CASCADE, related_name='parsing_errors',
         to=DocumentVersion, verbose_name=_('Document version')
diff --git a/mayan/apps/events/models.py b/mayan/apps/events/models.py
index 565c5e21d8..af9988d160 100644
--- a/mayan/apps/events/models.py
+++ b/mayan/apps/events/models.py
@@ -17,6 +17,9 @@ from .managers import (
 
 @python_2_unicode_compatible
 class StoredEventType(models.Model):
+    """
+    Model to mirror the real event classes as database objects.
+    """
     name = models.CharField(
         max_length=64, unique=True, verbose_name=_('Name')
     )
@@ -42,6 +45,10 @@ class StoredEventType(models.Model):
 
 @python_2_unicode_compatible
 class EventSubscription(models.Model):
+    """
+    This model stores the event subscriptions of an user for the entire
+    system.
+    """
     user = models.ForeignKey(
         db_index=True, on_delete=models.CASCADE,
         related_name='event_subscriptions', to=settings.AUTH_USER_MODEL,
@@ -64,6 +71,11 @@ class EventSubscription(models.Model):
 
 @python_2_unicode_compatible
 class Notification(models.Model):
+    """
+    This model keeps track of the notifications for an user. Notifications are
+    created when an event to which this user has been subscribed, are
+    commited elsewhere in the system.
+    """
     user = models.ForeignKey(
         db_index=True, on_delete=models.CASCADE,
         related_name='notifications', to=settings.AUTH_USER_MODEL,
diff --git a/mayan/apps/linking/models.py b/mayan/apps/linking/models.py
index 19af031945..06b2deaa52 100644
--- a/mayan/apps/linking/models.py
+++ b/mayan/apps/linking/models.py
@@ -16,6 +16,11 @@ from .managers import SmartLinkManager
 
 @python_2_unicode_compatible
 class SmartLink(models.Model):
+    """
+    This model stores the basic fields for a smart link. Smart links allow
+    linking documents using a programmatic method of conditions that mirror
+    Django's database filter operations.
+    """
     label = models.CharField(
         db_index=True, max_length=96, verbose_name=_('Label')
     )
@@ -43,6 +48,10 @@ class SmartLink(models.Model):
         return self.label
 
     def get_dynamic_label(self, document):
+        """
+        If the smart links was created using a template label instead of a
+        static label, resolve the template and return the result.
+        """
         if self.dynamic_label:
             context = Context({'document': document})
             try:
@@ -58,6 +67,10 @@ class SmartLink(models.Model):
             return None
 
     def get_linked_document_for(self, document):
+        """
+        Execute the corresponding smart links conditions for the document
+        provided and return the resulting document queryset.
+        """
         if document.document_type.pk not in self.document_types.values_list('pk', flat=True):
             raise Exception(
                 _(
@@ -100,6 +113,10 @@ class SmartLink(models.Model):
 
 
 class ResolvedSmartLink(SmartLink):
+    """
+    Proxy model to represent an already resolved smart link. Used for easier
+    colums registration.
+    """
     class Meta:
         proxy = True
 
@@ -109,6 +126,10 @@ class ResolvedSmartLink(SmartLink):
 
 @python_2_unicode_compatible
 class SmartLinkCondition(models.Model):
+    """
+    This model stores a single smart link condition. A smart link is a
+    collection of one of more smart link conditions.
+    """
     smart_link = models.ForeignKey(
         on_delete=models.CASCADE, related_name='conditions', to=SmartLink,
         verbose_name=_('Smart link')
diff --git a/mayan/apps/lock_manager/managers.py b/mayan/apps/lock_manager/managers.py
index 01a7405501..0493292b31 100644
--- a/mayan/apps/lock_manager/managers.py
+++ b/mayan/apps/lock_manager/managers.py
@@ -14,6 +14,11 @@ logger = logging.getLogger(__name__)
 
 class LockManager(models.Manager):
     def acquire_lock(self, name, timeout=None):
+        """
+        Attempts to acquire a lock. Return a LockError is the lock is already
+        held by someone else or if is not possible to acquire the lock due to
+        database or operational errors.
+        """
         logger.debug('trying to acquire lock: %s', name)
         lock = self.model(name=name, timeout=timeout)
 
diff --git a/mayan/apps/lock_manager/models.py b/mayan/apps/lock_manager/models.py
index a66e17a08a..d409036201 100644
--- a/mayan/apps/lock_manager/models.py
+++ b/mayan/apps/lock_manager/models.py
@@ -10,6 +10,9 @@ from .settings import setting_default_lock_timeout
 
 @python_2_unicode_compatible
 class Lock(models.Model):
+    """
+    Model to provide distributed resource locking using the database.
+    """
     creation_datetime = models.DateTimeField(
         auto_now_add=True, verbose_name=_('Creation datetime')
     )
@@ -30,6 +33,9 @@ class Lock(models.Model):
         return self.name
 
     def release(self):
+        """
+        Release a previously held lock.
+        """
         try:
             lock = Lock.objects.get(
                 name=self.name, creation_datetime=self.creation_datetime
diff --git a/mayan/apps/mailer/models.py b/mayan/apps/mailer/models.py
index d51fac223d..caa4cfcef4 100644
--- a/mayan/apps/mailer/models.py
+++ b/mayan/apps/mailer/models.py
@@ -33,6 +33,12 @@ class LogEntry(models.Model):
 
 
 class UserMailer(models.Model):
+    """
+    This model is used to create mailing profiles that can be used from inside
+    the system. These profiles differ from the system mailing profile in that
+    they can be created at runtime and can be assigned ACLs to restrict
+    their use.
+    """
     label = models.CharField(
         max_length=128, unique=True, verbose_name=_('Label')
     )
@@ -122,6 +128,9 @@ class UserMailer(models.Model):
                 self.error_log.all().delete()
 
     def send_document(self, document, to, subject='', body='', as_attachment=False):
+        """
+        Send a document using this user mailing profile.
+        """
         context_dictionary = {
             'link': 'http://%s%s' % (
                 Site.objects.get_current().domain,
@@ -153,6 +162,10 @@ class UserMailer(models.Model):
         )
 
     def test(self, to):
+        """
+        Send a test message to make sure the mailing profile settings are
+        correct.
+        """
         self.send(subject=_('Test email from Mayan EDMS'), to=to)
 
 
diff --git a/mayan/apps/metadata/models.py b/mayan/apps/metadata/models.py
index 5ef095dcca..542b7ceb35 100644
--- a/mayan/apps/metadata/models.py
+++ b/mayan/apps/metadata/models.py
@@ -40,7 +40,9 @@ def parser_choices():
 @python_2_unicode_compatible
 class MetadataType(models.Model):
     """
-    Define a type of metadata
+    Model to store a type of metadata. Metadata are user defined properties
+    that can be assigned a value for each document. Metadata types need
+    to be assigned to a document type before they can be used.
     """
     name = models.CharField(
         max_length=48,
@@ -127,6 +129,10 @@ class MetadataType(models.Model):
         return MetadataType.comma_splitter(template.render(context=context))
 
     def get_required_for(self, document_type):
+        """
+        Return a queryset of metadata types that are required for the
+        specified document type.
+        """
         return document_type.metadata.filter(
             required=True, metadata_type=self
         ).exists()
@@ -183,8 +189,8 @@ class MetadataType(models.Model):
 @python_2_unicode_compatible
 class DocumentMetadata(models.Model):
     """
-    Link a document to a specific instance of a metadata type with it's
-    current value
+    Model used to link an instance of a metadata type with a value to a
+    document.
     """
     document = models.ForeignKey(
         on_delete=models.CASCADE, related_name='metadata', to=Document,
@@ -218,9 +224,10 @@ class DocumentMetadata(models.Model):
 
     def delete(self, enforce_required=True, *args, **kwargs):
         """
-        enforce_required prevents deletion of required metadata at the
-        model level. It used set to False when deleting document metadata
-        on document type change.
+        Delete a metadata from a document. enforce_required which defaults
+        to True, prevents deletion of required metadata at the model level.
+        It used set to False when deleting document metadata on document
+        type change.
         """
         if enforce_required and self.metadata_type.pk in self.document.document_type.metadata.filter(required=True).values_list('metadata_type', flat=True):
             raise ValidationError(
@@ -241,6 +248,10 @@ class DocumentMetadata(models.Model):
 
     @property
     def is_required(self):
+        """
+        Return a boolean value of True of this metadata instance's parent type
+        is required for the stored document type.
+        """
         return self.metadata_type.get_required_for(
             document_type=self.document.document_type
         )
@@ -272,6 +283,10 @@ class DocumentMetadata(models.Model):
 
 @python_2_unicode_compatible
 class DocumentTypeMetadataType(models.Model):
+    """
+    Model used to store the relationship between a metadata type and a
+    document type.
+    """
     document_type = models.ForeignKey(
         on_delete=models.CASCADE, related_name='metadata', to=DocumentType,
         verbose_name=_('Document type')
diff --git a/mayan/apps/motd/models.py b/mayan/apps/motd/models.py
index a907e1af6d..2aeca9892b 100644
--- a/mayan/apps/motd/models.py
+++ b/mayan/apps/motd/models.py
@@ -9,6 +9,10 @@ from .managers import MessageManager
 
 @python_2_unicode_compatible
 class Message(models.Model):
+    """
+    Model to store an information message that will be displayed at the login
+    screen. Messages can have an activation and deactivation date.
+    """
     label = models.CharField(
         max_length=32, help_text=_('Short description of this message.'),
         verbose_name=_('Label')
diff --git a/mayan/apps/ocr/models.py b/mayan/apps/ocr/models.py
index 41b2a125b4..e06268f8f7 100644
--- a/mayan/apps/ocr/models.py
+++ b/mayan/apps/ocr/models.py
@@ -13,7 +13,7 @@ from .managers import (
 
 class DocumentTypeSettings(models.Model):
     """
-    Define for OCR for a specific document should behave
+    Model to store the OCR settings for a document type.
     """
     document_type = models.OneToOneField(
         on_delete=models.CASCADE, related_name='ocr_settings',
@@ -37,6 +37,9 @@ class DocumentTypeSettings(models.Model):
 
 @python_2_unicode_compatible
 class DocumentPageOCRContent(models.Model):
+    """
+    This model stores the OCR results for a document page.
+    """
     document_page = models.OneToOneField(
         on_delete=models.CASCADE, related_name='ocr_content',
         to=DocumentPage, verbose_name=_('Document page')
@@ -59,6 +62,10 @@ class DocumentPageOCRContent(models.Model):
 
 @python_2_unicode_compatible
 class DocumentVersionOCRError(models.Model):
+    """
+    This models keeps track of the errors captured during the OCR of a
+    document version.
+    """
     document_version = models.ForeignKey(
         on_delete=models.CASCADE, related_name='ocr_errors',
         to=DocumentVersion, verbose_name=_('Document version')
diff --git a/mayan/apps/permissions/models.py b/mayan/apps/permissions/models.py
index 186442a6c1..c0a8463c26 100644
--- a/mayan/apps/permissions/models.py
+++ b/mayan/apps/permissions/models.py
@@ -16,6 +16,11 @@ logger = logging.getLogger(__name__)
 
 @python_2_unicode_compatible
 class StoredPermission(models.Model):
+    """
+    This model is the counterpart of the permissions.classes.Permission
+    class. Allows storing a database counterpart of a permission class.
+    It is used to store the permissions help by a role or in an ACL.
+    """
     namespace = models.CharField(max_length=64, verbose_name=_('Namespace'))
     name = models.CharField(max_length=64, verbose_name=_('Name'))
 
@@ -34,9 +39,17 @@ class StoredPermission(models.Model):
             return self.name
 
     def get_volatile_permission_id(self):
+        """
+        Return the identifier of the real permission class represented by
+        this model instance.
+        """
         return '{}.{}'.format(self.namespace, self.name)
 
     def get_volatile_permission(self):
+        """
+        Returns the real class of the permission represented by this model
+        instance.
+        """
         return Permission.get(
             pk=self.get_volatile_permission_id(), proxy_only=True
         )
@@ -45,6 +58,12 @@ class StoredPermission(models.Model):
         return (self.namespace, self.name)
 
     def requester_has_this(self, user):
+        """
+        Helper method to check if an user has been granted this permission.
+        The check is done sequentially over all of the user's groups and
+        roles. The check is interrupted at the first positive result.
+        The check always returns True for superusers or staff users.
+        """
         if user.is_superuser or user.is_staff:
             logger.debug(
                 'Permission "%s" granted to user "%s" as superuser or staff',
@@ -70,6 +89,13 @@ class StoredPermission(models.Model):
 
 @python_2_unicode_compatible
 class Role(models.Model):
+    """
+    This model represents a Role. Roles are permission units. They are the
+    only object to which permissions can be granted. They are themselves
+    containers too, containing Groups, which are organization units. Roles
+    are the basic method to grant a permission to a group. Permissions granted
+    to a group using a role, are granted for the entire system.
+    """
     label = models.CharField(
         max_length=64, unique=True, verbose_name=_('Label')
     )
diff --git a/mayan/apps/tags/models.py b/mayan/apps/tags/models.py
index 7437d74b1c..c7b677aa43 100644
--- a/mayan/apps/tags/models.py
+++ b/mayan/apps/tags/models.py
@@ -19,6 +19,10 @@ from .widgets import widget_single_tag
 
 @python_2_unicode_compatible
 class Tag(models.Model):
+    """
+    This model represents a binary property that can be applied to a document.
+    The tag can have a label and a color.
+    """
     label = models.CharField(
         db_index=True, help_text=_(
             'A short text used as the tag name.'
@@ -41,6 +45,9 @@ class Tag(models.Model):
         return self.label
 
     def attach_to(self, document, user=None):
+        """
+        Attach a tag to a document and commit the corresponding event.
+        """
         self.documents.add(document)
         event_tag_attach.commit(
             action_object=self, actor=user, target=document
@@ -50,6 +57,10 @@ class Tag(models.Model):
         return reverse('tags:tag_tagged_item_list', args=(str(self.pk),))
 
     def get_document_count(self, user):
+        """
+        Return the numeric count of documents that have this tag attached.
+        The count if filtered by access.
+        """
         queryset = AccessControlList.objects.filter_by_access(
             permission_document_view, user, queryset=self.documents
         )
@@ -61,6 +72,9 @@ class Tag(models.Model):
     get_preview_widget.short_description = _('Preview')
 
     def remove_from(self, document, user=None):
+        """
+        Remove a tag from a document and commit the corresponding event.
+        """
         self.documents.remove(document)
         event_tag_remove.commit(
             action_object=self, actor=user, target=document
diff --git a/mayan/apps/user_management/models.py b/mayan/apps/user_management/models.py
index 1950332835..878a8c1bc6 100644
--- a/mayan/apps/user_management/models.py
+++ b/mayan/apps/user_management/models.py
@@ -8,6 +8,11 @@ from .managers import UserOptionsManager
 
 
 class UserOptions(models.Model):
+    """
+    This model stores administrative configurations for an user accounts.
+    At the moment it stores a boolean flag to restrict an user's
+    ability to change their password.
+    """
     user = models.OneToOneField(
         on_delete=models.CASCADE, related_name='user_options',
         to=settings.AUTH_USER_MODEL, unique=True, verbose_name=_('User')